CA1082298A - Direct spark ignition system utilizing gated oscillator - Google Patents
Direct spark ignition system utilizing gated oscillatorInfo
- Publication number
- CA1082298A CA1082298A CA272,209A CA272209A CA1082298A CA 1082298 A CA1082298 A CA 1082298A CA 272209 A CA272209 A CA 272209A CA 1082298 A CA1082298 A CA 1082298A
- Authority
- CA
- Canada
- Prior art keywords
- oscillator
- burner
- flame
- gate
- junction
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N5/00—Systems for controlling combustion
- F23N5/20—Systems for controlling combustion with a time programme acting through electrical means, e.g. using time-delay relays
- F23N5/203—Systems for controlling combustion with a time programme acting through electrical means, e.g. using time-delay relays using electronic means
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N5/00—Systems for controlling combustion
- F23N5/02—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium
- F23N5/12—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using ionisation-sensitive elements, i.e. flame rods
- F23N5/123—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using ionisation-sensitive elements, i.e. flame rods using electronic means
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23Q—IGNITION; EXTINGUISHING-DEVICES
- F23Q3/00—Igniters using electrically-produced sparks
- F23Q3/004—Using semiconductor elements
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N2227/00—Ignition or checking
- F23N2227/36—Spark ignition, e.g. by means of a high voltage
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N2229/00—Flame sensors
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N2231/00—Fail safe
- F23N2231/12—Fail safe for ignition failures
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N5/00—Systems for controlling combustion
- F23N5/02—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium
- F23N5/12—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using ionisation-sensitive elements, i.e. flame rods
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Control Of Combustion (AREA)
- Ignition Installations For Internal Combustion Engines (AREA)
Abstract
DIRECT SPARK IGNITION SYSTEM UTILIZING GATED OSCILLATOR
ABSTRACT OF THE DISCLOSURE
A system for trial period ignition of a fluid fuel burner having an oscillator with a gate In she feedback path thereof, the oscillator providing power to a burner fuel valve and to a spark generator, wherein oscillator operation is sustained after the period only upon flame detection which keeps the oscillator feedback path gate closed.
ABSTRACT OF THE DISCLOSURE
A system for trial period ignition of a fluid fuel burner having an oscillator with a gate In she feedback path thereof, the oscillator providing power to a burner fuel valve and to a spark generator, wherein oscillator operation is sustained after the period only upon flame detection which keeps the oscillator feedback path gate closed.
Description
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BAcKGRouND Q~ TIIE INVENTION
-This invention relates to fluid fuel combustion apparatus, and more particularly to a fail safe pilotless direct spark ignition system therefor.
In the past, oscillators have been employed in direct spark ignition systems. For example, see U.S. Patent No. 3,853,455~ llowever, such oscillators have been powered by current rectified by a flame rod.
SUMMARY OF THE INVENTION
In accordance with the system of the present invention, the above-described and other disadvantages of the prior art are overcome by providinga gated oscillator which is sustained in operation by a flame sensor. The gate thus requires little or no current or power to cause the oscillator to oscillate, which was not the case in the prior art.
According to the present invention, there is provided a direct spark ignition system, said system comprising: a fluid fuel burner; an electrically operable valve connected to said burner to control the fuel admitted thereto; an oscillator; a timing circuit actuable to cause said oscillator to oscillate Eor a predetermined period; a spark generator con-nected from said oscillator to ignite fuel emanating from said burner; and a flame sensor to sustain oscillations of said oscillator after said period when a flame exists at said burner, said oscillator including an amplifier having a feedback path with a gate connected therein, said flame sensor being connected to said gate to cause the same to close and to complete said feedback path in a manner to cause said oscillations to be sustained after said period when a flame exists at said burner, said flame sensor holding said gate open in the absence of flame to allow said oscillations to die out.
The above-described and other advantages of the present invention will be better understood from the following detailed description when con-sidered in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAl~INGS
In the drawings which are to be regarded as merely illustrative:
Fig. 1 is a schematic diagram of a direct spark ignition system
BAcKGRouND Q~ TIIE INVENTION
-This invention relates to fluid fuel combustion apparatus, and more particularly to a fail safe pilotless direct spark ignition system therefor.
In the past, oscillators have been employed in direct spark ignition systems. For example, see U.S. Patent No. 3,853,455~ llowever, such oscillators have been powered by current rectified by a flame rod.
SUMMARY OF THE INVENTION
In accordance with the system of the present invention, the above-described and other disadvantages of the prior art are overcome by providinga gated oscillator which is sustained in operation by a flame sensor. The gate thus requires little or no current or power to cause the oscillator to oscillate, which was not the case in the prior art.
According to the present invention, there is provided a direct spark ignition system, said system comprising: a fluid fuel burner; an electrically operable valve connected to said burner to control the fuel admitted thereto; an oscillator; a timing circuit actuable to cause said oscillator to oscillate Eor a predetermined period; a spark generator con-nected from said oscillator to ignite fuel emanating from said burner; and a flame sensor to sustain oscillations of said oscillator after said period when a flame exists at said burner, said oscillator including an amplifier having a feedback path with a gate connected therein, said flame sensor being connected to said gate to cause the same to close and to complete said feedback path in a manner to cause said oscillations to be sustained after said period when a flame exists at said burner, said flame sensor holding said gate open in the absence of flame to allow said oscillations to die out.
The above-described and other advantages of the present invention will be better understood from the following detailed description when con-sidered in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAl~INGS
In the drawings which are to be regarded as merely illustrative:
Fig. 1 is a schematic diagram of a direct spark ignition system
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constructed in accordance with the present invention; and Fig. 2 is a sche~atic diagram of a spark generator illustrated in Fig. 1.
DESCRIPTION OF TIIE PREFERRED EMBODIMENT
In accordance with the present invention, a heating device may be employed including a gas burner 10 as shown in Fig. 1 having a gas inlet 11 connected from a valve 12. Valve 12 is a solenoid valve having a solenoid winding illustrated at 13.
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E. A. Carlson-J. G. Raffaclli-R. ~. Ciann 7-6-1 The circuit of Fig. 1 is provicled with input terrninals 1~ and 15, terminal 14 bein~ positive ~ith respect to terminal 15.
A lead 16 is connected from terminal 15 through junctions 17, 18, 19, 20, 127, 21, 22, 23, 24 and 25. Junction 18 is grounded at 2Y. Similarly, 5 burner 10 is grounded at 28.
A thermostatic or other switch 29 is connected from junction 14 to a junction 30. A lead 31 is connected frorn switch 29 through junction 30, and a junction 31'.
A transformer is provided at 33 having a primary 34 and a secondary 35 . The upper end of secondary 35 is connected to a junction 37.
Junctions are provided at 38 and 39. A capacitor is provided at 40. Winding 13 and capacitor 40 are connected in parallel between junctions 38 and 39. Junctions 18 and 39 are connected together. A diode 41 is connected from ~unction 38 to junction 37 and poled to be conductive in a direction toward junction 37.
A spark generator 42 is connected from junction 37 to a spark elec~
trode 43.
Junction 44 is connected from junction 17 through a capacitor 46.
A Iamp 47 is connected between junctions 31' and 44.
The lower end of transformer secondary 35 is connected to junction 19 .
Junctionsareprovidedat48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 60 and 12 6 .
.~ .
E. A. Carlson-J. G. Raffaelli-R. A. Ganr, ~-6-1 A diode 62 is connected from junction 49 to junction 48 and poled to be conduetive in a direetion toward junction 48. A capacitor 63 is connected between junctions 48 and 54. A eonventional flame rod 64 is eonnected irom junction 54. A winding 65 is connected between junctions 44 and 50. An amplifier ineluding a transistor 66 iS provided, transistor 66 including a eolleetor 67, an emitter 68 and a base 69, transformer primary 34 being eon-neeted from junction 50 to eolleetor 67, emitter 68 being eonneeted to junetion 20. A resistor 70 is eonneeted from junetion 44 to junetion 51. Base 69 is eonneeted from junetion 51. Feedbaek to the amplifier is provided through a eapaeitor 71 and a eapaeitor 72. ~apaeitor 71 is eonneeted between june- -tions 51 and 52. Capaeitor 72 is eonnected between junctions 50 and 53. A
eonventional Darlington eireuit 73 is provided including a transistor 74 and a transistor 75. Transistor 74 has a collector 76 eonnected from junetion 52.
Transistor 74 has a base 77 eonnected to junction 53. Transistor 74 has an emitter 78 eonneeted to a base 79 of transistor 75. Transistor 75 also ineludes a eolleetor 80 eonnected from junction 52, and an emitter 81. A resistor 82 is eonneeted from emitter 81 to junction 21. A resistor 83 is eonneeted between junctions 49 and 52. Resistors 84 and 84' are connected between junctions 53, 53' and 53',54, respeetively. A resistor 85 is connected between junc-tions 3 li and 55 . A zener diode 86 is eonneeted between junetions 22 and 55. A eapaeitor 87 is eonneeted between junctions 56 and 49. ~unetions 55, 56 and 57 are eonneeted together.
A resistor 122 is eonneeted between junetions 53 and 23. A resistor 128 is eonneeted between junetions 126 and 127, junetions 51 and 126 being eonneeted together and to base 69.
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.' E. A. Carlson-J. G. Raflaelli-R. ~i. Ganrl 7-6-i ~ resistor 89 is conncctecl between junctions 57 and 60. A resistor 90 is connecl:ed between junctions 2~1 and 60. A capacitor 91 is connecled between junctions 25 and 60.
A silicon controlled rectifier (SCR) is provided at 92 including an anode 93, a cathode 94 and a gate 95. Anode 93 is connected from junction 57. Cathode 94 is connected to junction 25. Gate 95 is connected from junction 60.
OPERATION
In the operation of the direct spark ignition system of the present invention illustrated in Fig. 1, spark generator 42 may, if desired, be entirely conventional~ Spark generator 42 may be provided with an input lead 99 connected from junction 37 over which, during trial ignition, an A.C. signal is provided which is rectified and doubled or tripled in spark generator 42, stored in a capacitor and discharged from electrode 43 to burner 10 in the conventional way.
Trial ignition of burner 10 takes place when switch 29 is closed by a thermostat, manually or other~vise.
When switch 29 is closed, capaaitors 87 and 97 begin to charge.
The same is true of capacitor 91. When capacitor 91 charges to a sufficient degree, SCR 92 fires. Since junction 25 is at ground potential, when SCR
` 92 fires, junction~is automatically tied into ground potential. This means -that junction 5 6 is at ground potentia 1, and that junctions 4 9 a nd 5 3' a re at a pot 3ntia 1 below ground potential (capacitor 97 having been charged with the polarity shown in Fig. 1). The same is true of the charging polarities of capacitors 87 and 91.
~.
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~,~ r 1~ arlson-J . G . i~a'fclelli~ , ( ann 7-~;-1 In accordallce with the foregoing, the potential of junctio~ 53 is negatively driven. The same is true of thc potential of junction ~9. This causes the oscillator to oscillate. The base 77 of transistor 74 requires a negative bias. Note that the transistors 74 and 75 are PNP type transistors.
S The general circuit of the oscillator includes the ~ransis~or 66 having , ~
-` ~ the feedback irom junction 50 through capacitor 72 to the base 77 of tran-sistor 74. The ~arlington circuit then, acting as a gate, transmits the signal ; fed back through capacitor 71 to the base 69 of transistor 66.
When the charges on capacitors 87 and 97 finally fall to zero, the oscillator will no longer oscillate because a proper nesative bias is not then supplied to transistor base 77. However, if burner 10, during trial ignition, is in fact ignited by spark generator 42, flame rod 64 will act to build up a charge upon capacitor 63, which will turn the Darlington circuit or gate on and sùstain oscillator oscillations.
` 15 During trial ignition, winding 13 of valve 12 is energized and gas enters burner 10, If ignition is achieved, valve 12 thus remains open. If ignition is not achieved, the oscillator will no longer oscillate, winding 13 will nol be energized, valve 12 wil)i be closed, and burner 10 will no longer receive any gas or fluid fuel.
Spark Generator 42 is shown in greater detail in Fig, 2. In the con-:; .
struction of Fig. 2, as is conventional, spark generator 42 will not supply sparks to burner 10 via electrode 43 after ignition. This is true because one lead 100 of a transformer secondary 101 is connected to a junction 102 while th~ other lead 103 thereof is connected to electrode 43. A diode 104 rectifies , .: i ,' ~ , `' .
E. A. C~3rlson-J. G. Raffaelli-R. ~. C`;~nn 7-6-1 the si~nal appearing at one l~ad 9~, and is connected in series therewit~
and connected to be conductive toward a junction 105. Junctions 30 and 106 are connected together. Junctions 107, 108, 109 and 110 are additionally provided. A storaye capacitor 111 is connected between junctions 105 and 108, junction 108 beinggrounded at 112. ~unctions 108, 10~ and 110 are also con-nected together. An SCR 113 is provided having an anode 114, a cathode 115 and a gate 116. A unijunction transistor 117 fires SCR 113. A resistor 118 is connected between junctions 102 and 106. A transformer primary 119 is connected from junction 105 to anode 114. Cathode 115 is connected to junction 110. Gate 116 is connected to junction 107. A resistor 120 is connected be-tween junctions 107 and 110. A capacitor 121 is connected between junctions 102 and 109.
The spark generator 42 of Fig. 2 also includes junctions 123 and 124 connected respectively from junctions 102 and 109. A diode 125 is connected between junctions 124 and 123, and poled to be conductive in a direction toward junction 123.
The operation of the sparlc generator 42 shown in Fig. 2 is as follows.
The A.C, voltage impressed upon diode 104 is rectified thereby. Capacitor , 111 stores the rectified charge.
SCR 113 then fires at a delayed time based upon the time of firing of unijunction transistor 117, which is connected to SCR gate 116. The time of firing of the unijunction transistor 117 is determined by the potential of junction 102, this potential increasing with the flow of current through resistor 118 until it reaches the firing value of the emitter of unijunction 117. In other words, the firing time of transistor 117 is based upon the charging time of capacitor 121 . ~
. .
.
E. A. Carlson-J. G. RaIEaelli-R. A. Gann 7-6~1 When transistor 117 fires, SCR 113 is gated on. Capacitor 111 then '` discharges throu~h transformer primary 119, and a spark from electrode 43 to burner 10 ignites the burner 10. Once ignition has taken place, a high resistance `" ground also is produced between electrode 43 and the ~round of burner 10, which 5 ground is produced to effect an A.C. ground from junction 102 through capacitor 121. This is for discharge. There is also a D,C, resistance placed in parallel with capacitor 121 which prevents it from charging~ For this reason, transistor 117 cannot continually fir,e and fire SCR 1130 The connection of lead 100 to junction 102 thus disables the spark generator 42 when burner 10 has been 10 ignited.
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constructed in accordance with the present invention; and Fig. 2 is a sche~atic diagram of a spark generator illustrated in Fig. 1.
DESCRIPTION OF TIIE PREFERRED EMBODIMENT
In accordance with the present invention, a heating device may be employed including a gas burner 10 as shown in Fig. 1 having a gas inlet 11 connected from a valve 12. Valve 12 is a solenoid valve having a solenoid winding illustrated at 13.
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E. A. Carlson-J. G. Raffaclli-R. ~. Ciann 7-6-1 The circuit of Fig. 1 is provicled with input terrninals 1~ and 15, terminal 14 bein~ positive ~ith respect to terminal 15.
A lead 16 is connected from terminal 15 through junctions 17, 18, 19, 20, 127, 21, 22, 23, 24 and 25. Junction 18 is grounded at 2Y. Similarly, 5 burner 10 is grounded at 28.
A thermostatic or other switch 29 is connected from junction 14 to a junction 30. A lead 31 is connected frorn switch 29 through junction 30, and a junction 31'.
A transformer is provided at 33 having a primary 34 and a secondary 35 . The upper end of secondary 35 is connected to a junction 37.
Junctions are provided at 38 and 39. A capacitor is provided at 40. Winding 13 and capacitor 40 are connected in parallel between junctions 38 and 39. Junctions 18 and 39 are connected together. A diode 41 is connected from ~unction 38 to junction 37 and poled to be conductive in a direction toward junction 37.
A spark generator 42 is connected from junction 37 to a spark elec~
trode 43.
Junction 44 is connected from junction 17 through a capacitor 46.
A Iamp 47 is connected between junctions 31' and 44.
The lower end of transformer secondary 35 is connected to junction 19 .
Junctionsareprovidedat48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 60 and 12 6 .
.~ .
E. A. Carlson-J. G. Raffaelli-R. A. Ganr, ~-6-1 A diode 62 is connected from junction 49 to junction 48 and poled to be conduetive in a direetion toward junction 48. A capacitor 63 is connected between junctions 48 and 54. A eonventional flame rod 64 is eonnected irom junction 54. A winding 65 is connected between junctions 44 and 50. An amplifier ineluding a transistor 66 iS provided, transistor 66 including a eolleetor 67, an emitter 68 and a base 69, transformer primary 34 being eon-neeted from junction 50 to eolleetor 67, emitter 68 being eonneeted to junetion 20. A resistor 70 is eonneeted from junetion 44 to junetion 51. Base 69 is eonneeted from junetion 51. Feedbaek to the amplifier is provided through a eapaeitor 71 and a eapaeitor 72. ~apaeitor 71 is eonneeted between june- -tions 51 and 52. Capaeitor 72 is eonnected between junctions 50 and 53. A
eonventional Darlington eireuit 73 is provided including a transistor 74 and a transistor 75. Transistor 74 has a collector 76 eonnected from junetion 52.
Transistor 74 has a base 77 eonnected to junction 53. Transistor 74 has an emitter 78 eonneeted to a base 79 of transistor 75. Transistor 75 also ineludes a eolleetor 80 eonnected from junction 52, and an emitter 81. A resistor 82 is eonneeted from emitter 81 to junction 21. A resistor 83 is eonneeted between junctions 49 and 52. Resistors 84 and 84' are connected between junctions 53, 53' and 53',54, respeetively. A resistor 85 is connected between junc-tions 3 li and 55 . A zener diode 86 is eonneeted between junetions 22 and 55. A eapaeitor 87 is eonneeted between junctions 56 and 49. ~unetions 55, 56 and 57 are eonneeted together.
A resistor 122 is eonneeted between junetions 53 and 23. A resistor 128 is eonneeted between junetions 126 and 127, junetions 51 and 126 being eonneeted together and to base 69.
f.;~
.' E. A. Carlson-J. G. Raflaelli-R. ~i. Ganrl 7-6-i ~ resistor 89 is conncctecl between junctions 57 and 60. A resistor 90 is connecl:ed between junctions 2~1 and 60. A capacitor 91 is connecled between junctions 25 and 60.
A silicon controlled rectifier (SCR) is provided at 92 including an anode 93, a cathode 94 and a gate 95. Anode 93 is connected from junction 57. Cathode 94 is connected to junction 25. Gate 95 is connected from junction 60.
OPERATION
In the operation of the direct spark ignition system of the present invention illustrated in Fig. 1, spark generator 42 may, if desired, be entirely conventional~ Spark generator 42 may be provided with an input lead 99 connected from junction 37 over which, during trial ignition, an A.C. signal is provided which is rectified and doubled or tripled in spark generator 42, stored in a capacitor and discharged from electrode 43 to burner 10 in the conventional way.
Trial ignition of burner 10 takes place when switch 29 is closed by a thermostat, manually or other~vise.
When switch 29 is closed, capaaitors 87 and 97 begin to charge.
The same is true of capacitor 91. When capacitor 91 charges to a sufficient degree, SCR 92 fires. Since junction 25 is at ground potential, when SCR
` 92 fires, junction~is automatically tied into ground potential. This means -that junction 5 6 is at ground potentia 1, and that junctions 4 9 a nd 5 3' a re at a pot 3ntia 1 below ground potential (capacitor 97 having been charged with the polarity shown in Fig. 1). The same is true of the charging polarities of capacitors 87 and 91.
~.
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~,~ r 1~ arlson-J . G . i~a'fclelli~ , ( ann 7-~;-1 In accordallce with the foregoing, the potential of junctio~ 53 is negatively driven. The same is true of thc potential of junction ~9. This causes the oscillator to oscillate. The base 77 of transistor 74 requires a negative bias. Note that the transistors 74 and 75 are PNP type transistors.
S The general circuit of the oscillator includes the ~ransis~or 66 having , ~
-` ~ the feedback irom junction 50 through capacitor 72 to the base 77 of tran-sistor 74. The ~arlington circuit then, acting as a gate, transmits the signal ; fed back through capacitor 71 to the base 69 of transistor 66.
When the charges on capacitors 87 and 97 finally fall to zero, the oscillator will no longer oscillate because a proper nesative bias is not then supplied to transistor base 77. However, if burner 10, during trial ignition, is in fact ignited by spark generator 42, flame rod 64 will act to build up a charge upon capacitor 63, which will turn the Darlington circuit or gate on and sùstain oscillator oscillations.
` 15 During trial ignition, winding 13 of valve 12 is energized and gas enters burner 10, If ignition is achieved, valve 12 thus remains open. If ignition is not achieved, the oscillator will no longer oscillate, winding 13 will nol be energized, valve 12 wil)i be closed, and burner 10 will no longer receive any gas or fluid fuel.
Spark Generator 42 is shown in greater detail in Fig, 2. In the con-:; .
struction of Fig. 2, as is conventional, spark generator 42 will not supply sparks to burner 10 via electrode 43 after ignition. This is true because one lead 100 of a transformer secondary 101 is connected to a junction 102 while th~ other lead 103 thereof is connected to electrode 43. A diode 104 rectifies , .: i ,' ~ , `' .
E. A. C~3rlson-J. G. Raffaelli-R. ~. C`;~nn 7-6-1 the si~nal appearing at one l~ad 9~, and is connected in series therewit~
and connected to be conductive toward a junction 105. Junctions 30 and 106 are connected together. Junctions 107, 108, 109 and 110 are additionally provided. A storaye capacitor 111 is connected between junctions 105 and 108, junction 108 beinggrounded at 112. ~unctions 108, 10~ and 110 are also con-nected together. An SCR 113 is provided having an anode 114, a cathode 115 and a gate 116. A unijunction transistor 117 fires SCR 113. A resistor 118 is connected between junctions 102 and 106. A transformer primary 119 is connected from junction 105 to anode 114. Cathode 115 is connected to junction 110. Gate 116 is connected to junction 107. A resistor 120 is connected be-tween junctions 107 and 110. A capacitor 121 is connected between junctions 102 and 109.
The spark generator 42 of Fig. 2 also includes junctions 123 and 124 connected respectively from junctions 102 and 109. A diode 125 is connected between junctions 124 and 123, and poled to be conductive in a direction toward junction 123.
The operation of the sparlc generator 42 shown in Fig. 2 is as follows.
The A.C, voltage impressed upon diode 104 is rectified thereby. Capacitor , 111 stores the rectified charge.
SCR 113 then fires at a delayed time based upon the time of firing of unijunction transistor 117, which is connected to SCR gate 116. The time of firing of the unijunction transistor 117 is determined by the potential of junction 102, this potential increasing with the flow of current through resistor 118 until it reaches the firing value of the emitter of unijunction 117. In other words, the firing time of transistor 117 is based upon the charging time of capacitor 121 . ~
. .
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E. A. Carlson-J. G. RaIEaelli-R. A. Gann 7-6~1 When transistor 117 fires, SCR 113 is gated on. Capacitor 111 then '` discharges throu~h transformer primary 119, and a spark from electrode 43 to burner 10 ignites the burner 10. Once ignition has taken place, a high resistance `" ground also is produced between electrode 43 and the ~round of burner 10, which 5 ground is produced to effect an A.C. ground from junction 102 through capacitor 121. This is for discharge. There is also a D,C, resistance placed in parallel with capacitor 121 which prevents it from charging~ For this reason, transistor 117 cannot continually fir,e and fire SCR 1130 The connection of lead 100 to junction 102 thus disables the spark generator 42 when burner 10 has been 10 ignited.
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Claims (2)
1. A direct spark ignition system, said system comprising: a fluid fuel burner; an electrically operable valve connected to said burner to con-trol the fuel admitted thereto; an oscillator; a timing circuit actuable to cause said oscillator to oscillate for a predetermined period; a spark generator con-nected from said oscillator to ignite fuel emanating from said burner; and a flame sensor to sustain oscillations of said oscillator after said period when a flame exists at said burner, said oscillator including an amplifier having a feedback path with a gate connected therein, said flame sensor being con-nected to said gate to cause the same to close and to complete said feedback path in a manner to cause said oscillations to be sustained after said period when a flame exists at said burner, said flame sensor holding said gate open in the absence of flame to allow said oscillations to die out.
2. The invention as defined in claim 1, wherein said gate is a Darlington circuit having an input transistor with an input base, said flame sensor including a capacitor and a flame rod connected from said oscillator to a location over said burner, said capacitor being connected to said input transistor base to close said gate after said period when a flame exists between said burner and said flame rod and to open said gate when no such flame exists after said period.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/661,938 US4019854A (en) | 1976-02-27 | 1976-02-27 | Direct spark ignition system utilizing gated oscillator |
| US661,938 | 1976-02-27 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1082298A true CA1082298A (en) | 1980-07-22 |
Family
ID=24655722
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA272,209A Expired CA1082298A (en) | 1976-02-27 | 1977-02-21 | Direct spark ignition system utilizing gated oscillator |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US4019854A (en) |
| JP (1) | JPS52106033A (en) |
| AU (1) | AU505809B2 (en) |
| CA (1) | CA1082298A (en) |
| DE (1) | DE2707651A1 (en) |
| GB (1) | GB1528090A (en) |
| NL (1) | NL7701669A (en) |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4128387A (en) * | 1976-10-22 | 1978-12-05 | Paul T. Mu | Ignition device |
| US4124354A (en) * | 1977-06-03 | 1978-11-07 | International Telephone And Telegraph Corporation | Recycling pilot ignition system |
| US4145180A (en) * | 1977-11-29 | 1979-03-20 | Essex Group, Inc. | Ignition system for fuel burning apparatus |
| US4197082A (en) * | 1978-04-17 | 1980-04-08 | Johnson Controls, Inc. | Fuel ignition control arrangement employing dual flame sensors |
| US4299557A (en) * | 1979-10-02 | 1981-11-10 | Harper-Wyman Company | Fuel burner control circuit |
| US4435150A (en) | 1982-09-22 | 1984-03-06 | Emerson Electric Co. | Gas burner control system |
| US4565520A (en) * | 1984-01-30 | 1986-01-21 | Itt Corporation | Recycling pilot ignition system |
| DE3524090A1 (en) * | 1984-07-20 | 1986-01-30 | Hermes-Werke Leopold Herrmann GmbH, Wien | Ionisation flame sensor |
| US4696639A (en) * | 1986-11-06 | 1987-09-29 | Honeywell Inc. | Self-energizing burner control system for a fuel burner |
| DE4027090C2 (en) * | 1990-08-28 | 1998-07-23 | Kromschroeder Ag G | Arrangement for monitoring a burner flame |
| US5347982A (en) * | 1992-12-21 | 1994-09-20 | Canadian Heating Products Inc. | Flame monitor safeguard system |
| US5655900A (en) * | 1995-11-20 | 1997-08-12 | Harper-Wyman Company | Gas oven control system |
| GB9712447D0 (en) * | 1997-06-13 | 1997-08-13 | Contec Ltd | Flame detection and controlling the flow of gas to a burner |
| US5957679A (en) * | 1997-07-22 | 1999-09-28 | Harper-Wyman Company | Gas fireplace burner control system |
| US6985080B2 (en) * | 2003-03-07 | 2006-01-10 | Ranco Incorporated Of Delaware | Flame sense circuit and method with analog output |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3439991A (en) * | 1967-01-20 | 1969-04-22 | George H Fathauer | Dryer control |
| US3938938A (en) * | 1974-03-04 | 1976-02-17 | International Telephone And Telegraph Corporation | Ignition system and components thereof |
-
1976
- 1976-02-27 US US05/661,938 patent/US4019854A/en not_active Expired - Lifetime
- 1976-12-09 GB GB51437/76A patent/GB1528090A/en not_active Expired
-
1977
- 1977-01-14 JP JP346777A patent/JPS52106033A/en active Pending
- 1977-02-17 NL NL7701669A patent/NL7701669A/en not_active Application Discontinuation
- 1977-02-18 AU AU22451/77A patent/AU505809B2/en not_active Expired
- 1977-02-21 CA CA272,209A patent/CA1082298A/en not_active Expired
- 1977-02-23 DE DE19772707651 patent/DE2707651A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| JPS52106033A (en) | 1977-09-06 |
| DE2707651A1 (en) | 1977-09-01 |
| AU2245177A (en) | 1978-08-24 |
| GB1528090A (en) | 1978-10-11 |
| US4019854A (en) | 1977-04-26 |
| AU505809B2 (en) | 1979-12-06 |
| NL7701669A (en) | 1977-08-30 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |